Sanitary napkins and related disposable absorbent articles which collect menstrual discharges and protect against soiling of the wearer's clothing and bedding are well known in the art. These articles typically have a topsheet positioned against the body of the wearer, a backsheet which prevents the escape of bodily discharges from the sanitary napkin and an intermediate core which absorbs bodily discharges.
Sanitary napkins typically also have a means for attaching the sanitary napkin to the wearer's undergarment. For example, pressure sensitive adhesive on the outwardly oriented face of the backsheet has been long used in the art for this purpose. The adhesive on the outwardly oriented face of the backsheet is typically disposed in a rectangular patch or two longitudinally oriented and parallel strips, such as illustrated in U.S. Pat. No. 3,672,371, issued Jun. 27, 1972 to Roeder. As illustrated in the U.S. Pat. No. 3,672,371, the parallel strips may either be continuous or intermittent.
Improvements to such fastening means have also been attempted in the prior art. For example, U.S. Pat. No. 4,445,900, issued May 1, 1984 to Roeder discloses a sanitary napkin having an adhesive pattern in the form of two strips forming an X-shape crossing at the center of the napkin. Yet another attempt at providing an improved adhesion to the undergarment of the wearer is illustrated in U.S. Pat. No. 4,333,466, issued Jun. 8, 1982 to Matthews. This patent discloses adhesive which partially traces the outline of the perimeter of the sanitary napkin with concave outwardly oriented recesses.
The backsheet attachment means of the prior art suffer from the drawback that no allowance is made for the movements, particularly lateral extension, of the undergarment of the wearer. As the undergarment encounters the typical movements of the wearer, the attachment means of the backsheet may not be able to accommodate the stresses and deflections associated with such movements. Consequently, the means for attaching the sanitary napkin to the undergarment is stressed and may result in the sanitary napkin shifting from its intended position or, may, if the exerted forces are great enough, even result in the sanitary napkin becoming detached from the undergarment.
Another development which provides further protection against the soiling of bodily discharges and a means for positioning the sanitary napkin and attaching it to the undergarment is flaps which extend outwardly from each longitudinal edge of the sanitary napkin. Flaps which have been advantageously used with sanitary napkins are shown in U.S. Pat. No. 4,589,876, issued May 20, 1986 to Van Tilburg and U.S. Pat. No. 4,687,478, issued Aug. 18, 1987 to Van Tilburg, which patents are incorporated herein by reference for the purpose of showing particularly preferred executions of flaps used in conjunction with sanitary napkins.
These flaps also typically have adhesive disposed on the outwardly oriented face of the backsheet of the flap. While the specific form of the adhesive varies little, a typical execution is shown in U.S. Pat. No. 4,701,178, issued Oct. 20, 1987 to Glaug et al.
Flaps extending outwardly from the longitudinal edge of the napkin have also suffered from the drawbacks that, unless precisely and properly positioned, the flaps may not move with the undergarment of the wearer, may become detached if the forces exerted by the movements of the undergarment exceed the strength of the adhesive used to affix the flaps to the undergarment, and cannot fully accommodate shifting of the sanitary napkin while it is being worn.
It is an object of this invention to provide an improved means for attaching the sanitary napkin to the undergarment of the wearer. It is also an object of this invention to provide a backsheet and flaps for the sanitary napkin which tolerate movement and mispositioning of the sanitary napkin relative to the wearer's undergarments and which provide a more comfortably fitting sanitary napkin.